1. Field of Invention
The present invention refers to a motor control unit adapted for controlling an electronically driven hand held and/or hand guided tool. The tool comprises a housing and a working element located outside the housing. The tool's housing contains an electric motor and a gear mechanism for translating a rotational movement of the motor into an actuation movement of the working element.
Further, the invention refers to an electronically driven hand held and/or hand guided tool comprising a housing and a working element located outside the housing. The housing contains an electric motor and a gear mechanism for translating a rotational movement of the motor into an actuation movement of the working element. The tool comprises a motor control unit.
2. Description of Related Art
Electronically driven hand held and/or hand guided tools are well known in the prior art. They are also referred to as electric power tools or hand guided electric power tools. These tools comprise in particular grinders, polishers, sanders, glazing machines, planers, joining machines, edge trimmers, vertical routers, saws, scouring machines, drills, screwdrivers, and mixers. Depending on the type of tool and on the design of the gear mechanism and the working element, the working element can perform a rotational, an orbital, a random orbital, a roto-orbital, a planetary or a linear actuating movement.
In conventional electronically driven hand held and/or hand guided tools the control unit is an integral part of the tool's electronic components and fixedly located within the tool's housing. Each tool has its own control unit specifically adapted to the type of tool in terms of which sensor signals to receive from the motor, what maximum rotational speed of the working element can be reached, applied control strategy, etc. In particular, control parameters for controlling the tool and its motor, respectively, are preset to certain predefined values for the specific type of tool the control unit is adapted for. An electric cable for connecting the control unit and the other electronic components of the tool to an electric mains power supply enters the tool's housing, preferably at the rear part of the housing facing the user when operating the tool. Any power transformer means for transforming the energy originating from the mains power supply into energy suitable for the tool's electronic components and for operating the tool can be located inside the tool's housing, too. If the tool is provided with a switch for activating and deactivating the tool, this would be located within the housing and accessible by the user from outside the housing. If the tool comprises an actuator for setting a desired speed of the electric motor of the tool, this would be located within the housing, too.
In the prior art a separate control unit has to be provided for each tool due to the fact that the control unit is an integral part of the known tools. The control unit constitutes an important part of the tool in terms of proper functioning of the tool and in financial terms as well. Therefore, known tools are rather expensive. Furthermore, it almost impossible to provide existing tools with new control units comprising updated strategies of tool control and/or new energy saving techniques. The only possibility of providing existing tools with an updated control strategy would be to update control software of a control unit's microcontroller. However, this would require an interface to the microcontroller accessible from outside the tool and appropriate external hardware and software means for programming the microcontroller with the updated control software. Providing existing tools with new energy saving techniques is not possible at all because these new techniques usually require amended hardware components of the control unit.